XEye – Radiation-stable X-ray detectors

X-ray technology plays a central role in nondestructive material testing. The X-ray detector or X-ray image is crucial to the performance of this testing technology. While X-ray film was used as the primary imaging element in the past, digital X-ray detectors are now being used increasingly in both medical and industrial sectors. Because the detectors are exposed to the X-radiation as the image is recorded, it is critical for good, consistent image quality that the detectors have a high degree of radiation stability.

In industrial use, flat-panel detectors and conventional line scan cameras suffer irreversible damage after short periods of operation due to high radiation exposure and must be replaced. Because the scintillator does not completely absorb the X-rays, the semiconductor located directly behind it is damaged by the radiation. This becomes noticeable, for example, in pixel or column defects, or in the superimposition of various images, the so-called image lag.

The consistently high image quality and long service life of the XEye digital X-ray detector developed at the Fraunhofer Development Center for X-ray Technology (EZRT) in Fürth, Germany, ensures reliable results in industrial X-ray inspection over many years of use. Due to the detector’s robust image quality, image processing parameters no longer need to be updated for automatic fault detection.

The operating principle of these X-ray detectors is based on a digital scan of a luminous film (scintillator screen) that emits visible light when irradiated by X-rays. Multiple optical cameras capture overlapping areas of the image on the scintillator screen. These partial images are then merged seamlessly into the complete image. The patented radiation shielding concept that protects all of the optical and electronic components from radiation up to tube voltages of at least 225 kV ensures a long service life and the consistently high image quality of these X-ray detectors.

XEye X-ray detectors have been in continuous 24/7 use in a variety of industrial applications (e.g. inspection of welded seams) for more than 8 years without any detectable degradation in image quality. The automotive industry relies on XEye detectors for the inspection of cast suspension parts and wheels at production cycle. The high frame rate allows a production integrated computed tomography system to generate 3D data of engine pistons in less than 25 seconds. Fraunhofer EZRT X-ray detectors are also used in a variety of other industrial quality assurance applications, like inspection of solder joints in electronic modules, detection of foreign materials in foodstuffs or counting SMT-components in reels.

EZRT’s latest development is the high-resolution XEye5005 detector switchable between area and line mode with a pixel size of 50μm. When used as a line detector, it operates using the TDI-principle (Time Delayed Integration), capturing moving objects e.g. on a conveyor belt with a significantly improved image quality. TDI line detectors are also available as dual-energy versions with line widths of over 1 m.

When used as an area detector, the format of 50 x 5 cm² is ideally suited for helical computed tomography, providing 3D object data of exceptional quality.